Improving Migration and Population Statistics IMPS

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Improving Migration and Population Statistics
(IMPS)

• Amanda Blunden Jim Newman
• National Statistics Centre for Demography

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• Background to the Project
• Overview of the Projects Objectives
• Overview of the Areas of Research
• More Detail
• Local Authority Case Studies
• International Migration
• Internal Migration
• Administrative Data Sources

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Background 2001 Mid-Year Estimates
53.5m
53,225,000
Original inter-censal discrepancy of 1.1 million
52,084,000
51.5m
Rolled forward from 1991
Based on 2001 census
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Background 2001 Mid-Year Estimates
53.5m
- 351,000
- 305,000
Remaining unexplained difference of 209,000
275,000
51.5m
Rolled forward from 1991
Based on 2001 census
Revised 1991 post-census adjustment
International migration revisions
2001 post-census adjustments
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Background Mid-Year Estimates Methodology
Cohort Component Method
Estimated population at time T
Natural Change - add births, subtract deaths
International Migration - add inflows, subtract
outflows
Internal Migration - add inflows, subtract
outflows
Special Populations - UK armed forces, foreign
armed forces and dependants, prisoners, school
boarders
Estimated population at time T1
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Background Possible Weaknesses
Did the 2001 census under- or over-estimate the
population?
CENSUS BASE
Did the 2001 census incorrectly apportion the One
Number Census adjustments across local
authorities within census Estimation Areas?
Are there births that do not get registered?
BIRTHS
Are there births registered where the baby should
not be counted in the population?
Are there deaths that are not registered? Are
there deaths which are registered in the wrong LA?
DEATHS
Are there people who move but do not register in
the new area?
Are there adults who never register, so remain
counted where they were in full time education?
INTERNAL
MIGRATION
Are there people who move but the move is
incorrectly counted because they register in the
new area but were not registered in the old area?
Are asylum seekers coming in correctly allocated
to LAs?
Are asylum seekers who leave correctly subtracted
from LAs?
How are asylum seeker centres accounted for?
INTERNATIONAL
Are visitor switchers correctly allocated to LAs?
MIGRATION
Are other international migrants coming into the
UK correctly allocated to LAs?
Are other international migrants leaving the UK
correctly subtracted from LAs?
Are flows to and from Ireland correctly
apportioned to LAs?
DIFFICULT /
Armed Forces
School Boarders
Prisoners
Students
MOBILE GROUPS
Are sex ratios plausible?
NEW BASE
Are age / sex percentages plausible?
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Overview IMPS Key Objectives

• To improve the quality and reliability of
  migration and population statistics
• To ensure that the gap between the rolled forward
  mid-year estimates and the 2011 census results is
  not as large as was the case in 2001
• To ensure that ONS more fully understands the
  causes of/reasons for any gap that does occur in
  2011

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Overview IMPS Work Streams

• Population Base
• what population bases do users need?
• Alternative Data Sources
• nationally held data
• locally held data
• International Migration
• Internal Migration

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Local Authority (LA) Case Studies

• Investigate whether there are any locally held
  data sources which could be used to produce or
  quality assure the population statistics
• The selection of case study areas
• identify risk factors
• group LAs into clusters
• principal component analysis to identify clusters
  of interest
• LA nearest to centroid of each cluster selected

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LA Case Studies Risk Factors

• Gross international migration
• Gross internal migration
• Armed forces
• Non-white population
• Full-time students aged 18-74
• Prisoners
• Men aged 20-39
• Population density

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LA Case Studies Selected Clusters LAs

• Cluster 1
• high population density, migration rates and
  proportion of young males
• above national average proportions of students
  and non-white population
• Cluster 2
• high proportion of non-white population
• above national average population density,
  migration rates and proportions of students and
  young males
• Cluster 8
• above national average proportions of non-white
  population, students and young males
• Cluster 11
• high proportion of students

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Local Authority Case Studies Progress

• Selection of case study areas
• Requests to LAs to participate
• Carry out literature reviews
• Collate information dossiers
• First meetings with LAs
• Decide priority topics
• Carry out initial research
• Report initial findings to LAs

Nov 2005 Nov 2005 Dec 2005 Dec 2005 Jan 2006 Feb
2006 Mar 2006 May 2006
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International Migration Work Streams

• National Statistics Quality Review research
• International Passenger Survey (IPS) - migration
  questions and sampling
• methods used to integrate sources currently used
  to estimate international migration
• methods used for distributing IPS flows
  geographically within the UK
• potential use of existing alternative data
  sources to estimate international migration
• Other international migration research
• short-term international migration

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International Migration
Distribution of inflows within the UK, 2001
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International Migration
Distribution of inflows to LAs within GORs
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Internal Migration

• Research areas
• alternative data sources
• benefits data for children and older persons
• school census data for children
• student data
• the under-recording of young male migration
• is the migration of other groups under-recorded?
• ethnic minorities
• non-English speakers
• the introduction of walk-in centres
• the closure of GPs lists
• the assumptions for armed forces and their
  dependants

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Administrative Data Sources

• Research the potential use of
• National governmental sources
• schools census
• national insurance
• child benefit
• older persons
• electoral roll
• Local governmental sources
• council tax
• housing needs surveys
• Commercial sources
• utility companies
• commercial demographic databases (eg. ACORN)

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• Background to the Project
• Overview of the Projects Objectives
• Overview of the Areas of Research
• More Detail
• Local Authority Case Studies
• International Migration
• Internal Migration
• Administrative Data Sources

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Contact Details
Website http//www.statistics.gov.uk/imps E-mail
imps_at_ons.gov.uk Telephone Amanda (01329)
813524Jim [phone]